package PTA.MxduixiangX.ex03;

import java.util.Locale;
import java.util.Scanner;

public class ex03 {
    public static void main(String[] args) {
        Scanner sc= new Scanner(System.in);
        int n = sc.nextInt();
        sc.nextLine();
       StringBuilder sb = new StringBuilder();
        for(int i=0;i<n;i++){
            String line  =sc.nextLine();
            sb.append(line.split(":")[1]).append(" ");
        }
        String str[] = sb.toString().split(" ");
int count=0;
boolean f =true;
for(int i=0;i<str.length;i++){
    count = 0;
    for(int j =i+1;j<str.length;j++){
        if(str[i].equals(str[j])){
            count++;
        }
    }
    if(count == n-1){
        System.out.println(str[i]);
        f=true;
    }
}
if(!f){
    System.out.println("none");
}


    }
}
